From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: jmp <jasonpenilla2@me.com>
Date: Sat, 31 Oct 2020 11:49:01 -0700
Subject: [PATCH] Fix client lag on advancement loading

When new advancements are added via the UnsafeValues#loadAdvancement
API, it triggers a full datapack reload when this is not necessary. The
advancement is already loaded directly into the advancement registry,
and the point of saving the advancement to the Bukkit datapack seems to
be for persistence. By removing the call to reload datapacks when an
advancement is loaded, the client no longer completely freezes up when
adding a new advancement.
To ensure the client still receives the updated advancement data, we
manually reload the advancement data for all players, which
normally takes place as a part of the datapack reloading.

diff --git a/src/main/java/net/minecraft/server/AdvancementDataPlayer.java b/src/main/java/net/minecraft/server/AdvancementDataPlayer.java
index cc89bc1880a8c095942ba4e34c1bf4202e8dbedc..10da42010d8f3a6a7863d3b594ece33a5b130aa7 100644
--- a/src/main/java/net/minecraft/server/AdvancementDataPlayer.java
+++ b/src/main/java/net/minecraft/server/AdvancementDataPlayer.java
@@ -97,6 +97,7 @@ public class AdvancementDataPlayer {
 
     }
 
+    public final void reload(AdvancementDataWorld advancementDataWorld) { this.a(advancementDataWorld); } // Paper - OBFHELPER
     public void a(AdvancementDataWorld advancementdataworld) {
         this.a();
         this.data.clear();
@@ -393,6 +394,7 @@ public class AdvancementDataPlayer {
 
     }
 
+    public final void sendUpdateIfNeeded(EntityPlayer entityPlayer) { this.b(entityPlayer); } // Paper - OBFHELPER
     public void b(EntityPlayer entityplayer) {
         if (this.m || !this.i.isEmpty() || !this.j.isEmpty()) {
             Map<MinecraftKey, AdvancementProgress> map = Maps.newHashMap();
diff --git a/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java b/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java
index 25af57d0ab191f6a29ae95cec764667e9c23bdd4..4b7ca6d2e13fad43a75a345608b739f47adba738 100644
--- a/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java
+++ b/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java
@@ -289,7 +289,13 @@ public final class CraftMagicNumbers implements UnsafeValues {
                     Bukkit.getLogger().log(Level.SEVERE, "Error saving advancement " + key, ex);
                 }
 
-                MinecraftServer.getServer().getPlayerList().reload();
+                // Paper start
+                //MinecraftServer.getServer().getPlayerList().reload();
+                MinecraftServer.getServer().getPlayerList().getPlayers().forEach(player -> {
+                    player.getAdvancementData().reload(MinecraftServer.getServer().getAdvancementData());
+                    player.getAdvancementData().sendUpdateIfNeeded(player);
+                });
+                // Paper end
 
                 return bukkit;
             }